Semiconductor package and method of manufacturing the semiconductor package

ABSTRACT

A semiconductor package includes: a first semiconductor device including a first pad and a first metal bump structure on the first pad; and a second semiconductor device on the first semiconductor device, and including a third pad and a second metal bump structure on the third pad, wherein the first and second metal bump structures are bonded to each other to electrically connect the first and second semiconductor devices to each other. Each of the first and second metal bumps structures includes first to third metal patterns. The first to third metal patterns of the first metal bump structure are on the first pad. The first to third metal patterns of the second metal bump structure are on the third pad. The first and third metal patterns include a first metal having a first coefficient of thermal expansion less than that of a second metal of the second metal pattern.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2020-0102791, filed on Aug. 14, 2020 in the Koreanintellectual Property Office (KIPO), the disclosure of which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

Exemplary embodiments of the present inventive concept relate to asemiconductor package and a method of manufacturing the semiconductorpackage. More particularly, exemplary embodiments of the presentinventive concept relate to a semiconductor package includingsemiconductor chips bonded to each other and a method of manufacturingthe same.

DISCUSSION OF THE RELATED ART

As a pitch between chip pads decreases, side wetting may occur wheresolder flows along a side of a UBM pattern. To prevent side wetting,copper to copper bonding (Cu—Cu Bonding) technology is currently underdevelopment. However, in a case of copper-copper bonding, sincesufficient diffusion at a junction may occur, a relatively hightemperature and pressure may be desired, and bonding properties maydeteriorate.

SUMMARY

According to an exemplary embodiment of the present inventive concept, asemiconductor package includes: a first semiconductor device including afirst pad and a first metal bump structure provided on the first pad;and a second semiconductor device stacked on the first semiconductordevice, and including a third pad and a second metal bump structureprovided on the third pad, wherein the first and second metal bumpstructures are bonded to each other to form a conductive connector thatelectrically connects the first and second semiconductor devices to eachother, wherein each of the first and second metal bumps structuresincludes first, second and third metal patterns, wherein the first,second and third metal patterns of the first metal bump structure arestacked on the first pad, wherein the first, second and third metalpatterns of the second metal bump structure are stacked on the thirdpad, and wherein the first and third metal patterns include a firstmetal having a first coefficient of thermal expansion, and the secondmetal pattern includes a second metal having a second coefficient ofthermal expansion greater than the first coefficient of thermalexpansion.

According to an exemplary embodiment of the present inventive concept, asemiconductor package includes; a first semiconductor device including afirst pad and a first metal bump structure provided on the first pad;and a second semiconductor device stacked on the first semiconductordevice, and including a third pad and a second metal bump structureprovided on the third pad, wherein each of the first and second metalbump structures includes: a main pattern including copper (Cu), whereinthe main pattern of the first metal bump structure is provided on thefirst pad, and the main pattern of the second metal bump structure isprovided on the third pad; and a sub pattern provided inside the mainpattern adjacent to a junction surface and including a second metalhaving a coefficient of thermal expansion greater than that of copper(Cu), and wherein the junction surface is formed by the bonding betweena first surface of the main pattern of the first metal bump structureand a first surface of the main pattern of the second metal bumpstructure.

According to an exemplary embodiment of the present inventive concept, asemiconductor package includes: a package substrate; a firstsemiconductor chip stacked on the package substrate, and including afirst pad and a first metal bump structure provided on the first pad;and a second semiconductor chip stacked on the first semiconductor chip,and including a third pad and a second metal bump structure provided onthe third pad, wherein the first and second metal bump structures arebonded to each other to form a conductive connector that electricallyconnects the first and second semiconductor chips to each other, whereineach of the first and second metal bumps structures includes first,second and third metal patterns, wherein the first, second and thirdmetal patterns of the first metal bump structure are stacked on thefirst pad, wherein the first, second and third metal patterns of thesecond metal bump structure are stacked on the third pad, wherein thefirst and third metal patterns includes copper (Cu), and the secondmetal pattern includes a metal having a coefficient of thermal expansiongreater than that of copper (Cu), and wherein diameters of the first andsecond metal bump structures, respectively, are within a range of about2 μm to about 15 μm.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present inventive concept willbecome more apparent by describing in detail exemplary embodimentsthereof, with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view illustrating a semiconductor package inaccordance with an exemplary embodiment of the present inventiveconcept.

FIG. 2 is an enlarged cross-sectional view illustrating portion ‘A’ inFIG. 1.

FIGS. 3. 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and20 are cross-sectional views illustrating a method of manufacturing asemiconductor package in accordance with an exemplary embodiment of thepresent inventive concept.

FIG. 22 is a cross-sectional view illustrating a semiconductor packagein accordance with an exemplary embodiment of the present inventiveconcept.

FIGS. 23, 24, 25, 26, 27, 28 and 29 are cross-sectional viewsillustrating a method of manufacturing a semiconductor package inaccordance with an exemplary embodiment of the present inventiveconcept.

FIG. 30 is a cross-sectional view illustrating a semiconductor packagein accordance with an exemplary embodiment of the present inventiveconcept.

FIGS. 31, 32, 33, 34, 35 and 36 are cross-sectional views illustrating amethod of manufacturing a semiconductor package in accordance with anexemplary embodiment of the present inventive concept.

FIG. 37 is a cross-sectional view illustrating a semiconductor packagein accordance with an exemplary embodiment of the present inventiveconcept.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, exemplary embodiments of the present inventive concept willbe explained in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view illustrating a semiconductor package inaccordance with an exemplary embodiment of the present inventiveconcept. FIG. 2 is an enlarged cross-sectional view illustrating portion‘A’ in FIG. 1.

Referring to FIGS. 1 and 2, a semiconductor package 10 may includesemiconductor chips stacked therein. The semiconductor package 10 mayinclude a package substrate 100, first and second semiconductor chips200 and 300 sequentially stacked on the package substrate 100, and aconductive connector provided between the first and second semiconductorchips 200 and 300 and configured to electrically connect the first andsecond semiconductor chips 200 and 300 to each other. Additionally, thesemiconductor package 10 may further include conductive bumps 150, outerconnection members 130, and a molding member 500. The conductive bumps150 may electrically connect the package substrate 100 and the firstsemiconductor chip 200 to each other. The outer connection members 130may be electrically connected with an external device.

A plurality of the semiconductor chips 200 and 300 may be stackedvertically. In this embodiment, the first and second semiconductor chips200 and 300 may be substantially the same or similar to each other.Thus, the same or like reference numerals will be used to refer to thesame or like elements and repeated descriptions of the same elements maybe omitted.

Although the semiconductor package, which is a multi-chip package, isillustrated as including two stacked semiconductor chips 200 and 300,however, the present inventive concept may not be limited thereto. Forexample, the semiconductor package may include 4, 8, 12, or 16 stackedsemiconductor chips.

Each of the first and second semiconductor chips 200 and 300 may includean integrated circuit chip formed by performing semiconductormanufacturing processes. Each of the semiconductor chips may include,for example, a memory chip or a logic chip.

Hereinafter, the first semiconductor chip 200 will be explained indetail.

The first semiconductor chip 200 may include a substrate 210 and a firstpad 230 provided on a first surface of the substrate 210. Additionally,the first semiconductor chip 200 may further include an insulationinterlayer 220 and a through electrode 250. The insulation interlayer220 may be provided on the first surface of the substrate 210, and thethrough electrode 250 may penetrate the substrate 210.

An insulation interlayer 220 may be provided on the first surface, forexample, an active surface of the substrate 210. Circuit patterns may beprovided in the active surface of the substrate 210. The circuitpatterns may include a transistor, a diode, etc. The circuit patternsmay constitute circuit elements. Accordingly, the first semiconductorchip 200 may be a semiconductor device including a plurality of thecircuit elements therein.

The insulation interlayer 220 may include a plurality of insulationlayers 220 a, 220 b, 220 c, 220 d, 220 e and a wiring 222 in theinsulation layers. The wiring 222 may include a first metal wiring 222a, a first contact 222 b, a second metal wiring 222 c, a second contact222 c, and a third metal wiring 230 respectively provided in theinsulation layers 220 a, 220 b, 220 c, 220 d, 220 e. At least a portionof the third metal wiring 230 may serve as the first pad (e.g., alanding pad).

An insulation layer pattern 224 may be provided on the insulationinterlayer 220 to expose at least portions of the first pads 230. Forexample, the insulation layer pattern 224 may be a passivation layer.

The through electrode 250 may penetrate the substrate 210 in a thicknessdirection to contact the first metal wiring 222 a. Accordingly, thethrough electrode 250 may be electrically connected to the first pad 230through the wiring 222 disposed in the insulation interlayer 220.

A liner layer may be provided on an outer surface of the throughelectrode 250. For example, the liner layer may include silicon oxide orcarbon doped silicon oxide. The liner layer may electrically insulatethe substrate 110 and the insulation interlayer 220 from the throughelectrode 250.

An insulation layer 262 may be provided on a second surface, forexample, a backside surface of the substrate 110. A second pad 260 maybe provided in the insulation layer 262, The insulation layer 262 mayinclude, for example, silicon oxide, carbon doped silicon oxide, siliconcarbon nitride (SiCN), etc. Accordingly, the first and second pads 230and 260 may be electrically connected to each other by the throughelectrode 250.

In an exemplary embodiment of the present inventive concept, the secondsemiconductor chip 300 may include a substrate 310 and a third pad 330provided on a first surface of the substrate 310. Similar to the firstsemiconductor chip 200, an insulation layer pattern 324 may be providedon an insulation interlayer 320 and may expose at least portions of thethird pads 330. For example, the insulation layer pattern 324 may be apassivation layer.

The second semiconductor chip 300 may be stacked on the firstsemiconductor chip 200 such that the third pad 330 of the secondsemiconductor chip 300 faces the first pad 230 of the firstsemiconductor chip 200. A filling support layer pattern 402 may beinterposed between the first and second semiconductor chips 200 and 300.For example, the filling support layer pattern 402 may be an adhesivemember.

In an exemplary embodiment of the present inventive concept, theconductive connector may include a metal pillar structure interposedbetween the first and third pads 230 and 330 of the first and secondsemiconductor chips 200 and 300. The conductive connector may include afirst metal bump structure 240, which is provided on the first pad 230of the first semiconductor chip 200, and a second metal bump structure340, which is provided on the third pad 330 of the second semiconductorChip 300. The first and second metal bump structures 240 and 340 may hebonded to each other to serve as an electrical connector forelectrically connecting the first and second semiconductor chips 200 and300 to each other. For example, each of the first and second metal bumpstructures 240 and 340 may have a cuboid shape, a cylindrical shape or atriangular prism shape. The first and second metal bump structures 240and 340 may be substantially the same as or similar to each other. Thus,the same or like reference numerals will be used to refer to the same orlike elements and repeated descriptions of the same elements may beomitted.

As illustrated in FIG. 2, each of the first and second metal bumpstructure 240 and 340 may include a main pattern respectively providedon the first and third pads 230 and 330. The main pattern may include afirst metal. In addition, each of the first and second metal bumpstructure 240 and 340 may further include a sub pattern provided insidethe main pattern adjacent to a junction surface I. For example, thejunction surface I may be the bonding between a first surface of thethird metal pattern 246 of the first metal bump structure 240 and afirst surface of the third metal pattern 346 of the second metal bumpstructure 340. The sub pattern may include a second metal having acoefficient of thermal expansion greater than the first metal.

For example, the first metal may include copper (Cu). However, thepresent inventive concept may not be limited thereto, and the firstmetal may include a material (e,g, gold (Au)) that can be bonded byinter-diffusion of metal performed by a high-temperature annealingprocess.

The second semiconductor chip 300 may be stacked on the firstsemiconductor chip 200 such that the third pad 330 faces the first pad230. Accordingly, the first metal bump structure 240, which is on thefirst pad 230, and the second metal bump structure 340, which is on thethird pad 330, may be in contact with each other. For example, the firstand second metal bump structures 240 and 340 may be bonded to each otherby a high-temperature annealing process while in contact with each other(e.g., Cu—Cu Bonding).

For example, the first metal bump structure 240 may include first tothird metal patterns 242, 244, 246 sequentially stacked on the first pad230. The first and third metal patterns 242 and 246 may each include thefirst metal having a first coefficient of thermal expansion. The secondmetal pattern 244 may include the second metal having a secondcoefficient of thermal expansion. For example, the first and third metalpatterns 242 and 246 may serve as the main pattern, and the second metalpattern 244 may serve as the sub pattern.

For example, the first metal of the first and third metal patterns 242and 246 may include copper (Cu), and the second metal of the secondmetal pattern 244 may include zinc (Zn), aluminum (Al), silver (Ag),etc. The coefficient of thermal expansion of copper (Cu) may be about16.5 μm/m·K. The coefficient of thermal expansion of zinc (Zn) may beabout 25.0 μm/m·K. The coefficient of thermal expansion of aluminum (Al)may be about 23.03 μm/m·K. The coefficient of thermal expansion ofsilver (Ag) may be about 19.2 μm/m·K.

A diameter of the first metal bump structure 240 may be within a rangeof about 2 μm to about 15 μm. A height of the first metal bump structure240 may be within a range of about 2 μm to about 30 μm. A pitch Pbetween the first pads 230 and/or between the third pads 330 may bewithin a range of about 10 μm to about 20 μm.

The first metal pattern 242 may have a first thickness T1. The secondmetal pattern 244 may have a second thickness T2 smaller than the firstthickness T1, and the third metal pattern 246 may have a third thicknessT3 smaller than or the same as the second thickness T2. The firstthickness T1 may be within a range of about 70% to about 85% of theheight (e.g., thickness) of the first metal bump structure 240. Thesecond thickness T2 may be within a range of about 10% to about 20% ofthe height of the first metal bump structure 240, and the thirdthickness T3 may be within a range of about 5% to about 10% of theheight of the first metal bump structure 240.

In an exemplary embodiment of the present inventive concept, the firstmetal pattern 242, the second metal pattern 244 and the third metalpattern 246 may have the same thickness as each other.

Similarly, the second metal bump structure 340 may include first tothird metal patterns 342, 344, 346 sequentially stacked on the third pad330.

The third metal patterns 246 and 346 of the first and second metal bumpstructures 240 and 340, respectively, may be bonded to each other by thehigh-temperature annealing process while in contact with each other.Since the second metal patterns 244 and 344 disposed on the third metalpatterns 246 and 346 include the metal having the coefficient of thermalexpansion greater than that of copper, a local load may be applied tothe third metal patterns 246 and 346 to induce a sufficient diffusion atthe junction 1 between the first metal bump structure 240 and the secondmetal bump structure 340 during the high-temperature thermal compressionprocess, thereby providing excellent bonding properties.

In an exemplary embodiment of the present inventive concept, theconductive bump 150 may be interposed between the package substrate 100and the first semiconductor chip 200. The conductive bump 150 mayelectrically connect a substrate pad of the package substrate 100 and asecond pad 260 of the first semiconductor chip 200 to each other. Forexample, the conductive bump 150 may have a diameter of about 10 μm toabout 100 μm.

The molding member 500 may be provided on the package substrate 100 tocover the first and second semiconductor chips 200 and 300. For example,the molding member 500 may include an epoxy-based, polyimide-based, oracrylic-based material.

The outer connection members 130 may be provided on the outer connectionpads on a lower surface of the package substrate 100.

Hereinafter, a method of manufacturing the semiconductor package in FIG.1 will be explained.

FIGS. 3 to 20 are cross-sectional views illustrating a method ofmanufacturing a semiconductor package in accordance with an exemplaryembodiment of the present inventive concept. FIGS. 4 to 10 are enlargedcross-sectional views illustrating portion ‘B’ in FIG. 3. FIG. 14 is anenlarged cross-sectional view illustrating portion ‘C’ in FIG. 13. FIG.17 is an enlarged cross-sectional view illustrating portion ‘D’ in FIG.16.

Referring to FIGS. 3 to 11, second metal bump structures 340 may beformed on third pads 330 of a second semiconductor chip, respectively.

As illustrated in FIG. 3, a second wafer W2 including the secondsemiconductor chip in a wafer level may be prepared.

In an exemplary embodiment of the present inventive concept, the secondwafer W2 may include a substrate 310 and the third pad 330 provided on afirst surface 312 of the substrate 310. The substrate 310 may include adie region DA, where circuit patterns and cells are formed, and a scribelane region SA at least partially surrounding the die region DA. Asdescribed later, the substrate 310 may be sawed along the scribe laneregion SA dividing the die regions DA to form an individualsemiconductor chip.

For example, the substrate 310 may include silicon, germanium,silicon-germanium, or III-V compounds, e.g., GaP, GaAs, GaSb, etc. In anexemplary embodiment of the present inventive concept, the substrate 310may be a silicon-on-insulator (SOI) substrate, or agermanium-on-insulator (GOI) substrate.

As illustrated in FIG. 4, an insulation interlayer 320 may be providedon the first surface of the substrate 310, for example, an activesurface. Circuit patterns may be provided in the active surface of thesubstrate 310. The circuit patterns may include a transistor, a diode,etc. The circuit patterns may constitute circuit elements.

The insulation interlayer 320 may include a plurality of insulationlayers 320 a, 320 b, 320 c, 320 d, 320 e and a wiring 322 in theinsulation layers. The wiring 322 may include a first metal wiring 322a, a first contact 322 b, a second metal wiring 322 d and a third metalwiring 330 respectively provided in the insulation layers 320 a, 320 b,3220 c, 320 d, 320 e. At least a portion of the third metal wiring 330may serve as the third pad, which may be, for example, a landing pad.For example, the third pad 330 may be provided in a front side of thesecond wafer W2, which is, hereinafter, referred to as the first surface312 of the substrate 310 for simplicity of explanation.

For example, the third pad 330 may include a metal such as aluminum,copper, etc. A pitch P between the third pads 330 may be within a rangeof about 10 μm to about 20 μm.

Then, the second metal bump structures 340 may be formed on third pads330 of the second wafer W2, respectively.

As illustrated in FIG. 5, an insulation layer pattern 324 may be formedon the first surface 312 of the substrate 310 to expose the third pads330, and then, a seed layer 22 may be formed on the third pads 330.

The insulation layer pattern 324, as a passivation layer, may be formedon the insulation interlayer 320 and may expose at least portions of thethird pads 330. For example, the insulation layer pattern 324 mayinclude oxide, nitride, etc. These may be used alone or in a mixturethereof. Additionally, the insulation layer pattern 324 may be formedby, for example, a chemical vapor deposition (CVD) process, a plasmaenhanced chemical vapor deposition (PENCVD) process, an atomic layerdeposition (ALD) process, a lower pressure chemical vapor deposition(LPCVD) process, a sputtering process, etc. In addition, the insulationlayer pattern 324 may include a polymer layer formed by a spin coatingprocess or a spray process. In a case that a protective layer patternfor exposing the third pad 330 is formed on the first surface 312 of thesubstrate 310, the process of formed the insulation layer pattern may beomitted.

For example, the seed layer 22 may include an alloy layer includingtitanium/copper (Ti/Cu), titanium/palladium (Ti/Pd), titanium/nickel(Ti/Ni), chrome/copper (Cr/Cu) or a combination thereof.

Then, as illustrated in FIG. 6, a photoresist pattern 30 having anopening 31, which exposes a region of the seed layer 22 on the third pad330 may be formed on the first surface 312 of the substrate 310.

First, a photoresist layer may be formed on the first surface 312 of thesubstrate 310 to cover the seed layer 22.

For example, a thickness of the photoresist layer may be within a rangeof about 2 μm to about 40 μm. The thickness of the photoresist layer maybe selected in consideration of, for example, a height of the metal bumpstructure, deformation, process margin, etc.

An exposure process may be performed on the photoresist layer to formthe photoresist pattern 30 having the opening 31 which exposes theregion of the seed layer 22 on the third pad 330. For example, adiameter D1 of the opening 31 may be within a range of about 2 μm toabout 15 μm.

As illustrated in FIG. 7, a first plating process may be performed onthe seed layer 22 to form a first metal pattern 342 on the seed layer 22and including a first metal material.

For example, the first metal material may include copper (Cu). The firstmetal pattern 342 may have a first coefficient of thermal expansion. Thefirst metal pattern 342 may have a first thickness T1. The coefficientof thermal expansion of copper (Cu) may be about 16.5 μm/m·K.

As illustrated in FIG. 8, a second plating process may be performed onthe first metal pattern 342 to form a second metal pattern 344 includinga second metal material.

For example, the second metal material may include zinc (Zn), aluminum(Al), silver (Ag), etc. The second metal material may have a secondcoefficient of thermal expansion greater than the first coefficient ofthermal expansion of the first metal material. The second metal pattern344 may have a second thickness T2 smaller than the first thickness T1.The coefficient of thermal expansion of zinc (Zn) may be about 25.0μm/m·K. The coefficient of thermal expansion of aluminum (Al) may beabout 23.03 μm/m·K. The coefficient of thermal expansion of silver (Ag)may be about 19.2 μm/m·K.

As illustrated in FIG. 9, a third plating process may be performed onthe second metal pattern 344 to form a third metal pattern 346 includinga third metal material.

For example, the third metal material may include the same metal as thefirst metal material. The third metal pattern 346 may have a thirdthickness T3 smaller than the second thickness T2.

As illustrated in FIGS. 10 and 11, the photoresist pattern 30 may beremoved to form the second metal bump structure 340 including the firstto third metal patterns 342, 344, and 346 on the third pad 330 on thesubstrate 310. In this case, the seed layer 22 may be partially etchedto form a seed layer pattern 24.

A diameter of the second metal bump structure 340 may be within a rangeof about 2 μm to about 15 μm. The second metal bump structure 340 mayhave a second height from the first surface 312 of the substrate 310.The second height may be within a range of about 2 μm to about 30 μm.The first thickness T1 of the first metal pattern 342 may be within arange of about 70% to about 85% of the second height of the second metalbump structure 340. The second thickness T2 of the second metal pattern344 may be within a range of about 10% to about 20% of the second heightof the second metal bump structure 340. The third thickness T3 of thethird metal pattern 346 may be within a range of about 5% to about 10%of the second height of the second metal bump structure 340.

Accordingly, the second metal bump structure 340 may include the firstand second main metal patterns 342 and 346 including the pillar-shapedcopper material and the sub metal pattern 344 interposed therebetweenand including the metal having the coefficient of thermal expansiongreater than that of copper.

Referring to FIGS. 12 to 15, first metal bump structures 240 may beformed on first pads 230 of a first semiconductor chip, respectively.

As illustrated in FIG. 12, a first wafer W1 including the firstsemiconductor chip in a wafer level may be prepared.

In an exemplary embodiment of the present inventive concept, the firstwafer W1 may include a substrate 210, the first pad 230 provided on afirst surface 212 of the substrate 210, and a through electrode 250. Thesubstrate 210 may include a die region DA and a scribe lane region SA.The die region DA is a region where circuit patterns and cells areformed, and the scribe lane region SA at least partially surrounds thedie region DA. As described later, the substrate 210 may be sawed alongthe scribe lane region SA dividing the die regions DA to form anindividual semiconductor chip.

As illustrated in FIG. 14, the through electrode 250 may be provided topenetrate the substrate 210. The through electrode 250 may beelectrically connected to the first pad 230 through a wiring 222 in aninsulation interlayer 220. The through electrode 250 may be formedbefore polishing a backside surface of the substrate 210, for example, asecond surface 214 as illustrated in FIG. 19 (via first process and viamiddle process). In addition, the through electrode 250 may be formedafter polishing the backside surface of the substrate 210 as illustratedin FIG. 19 (via last process).

As illustrated in FIGS. 13 and 14, processes the same as or similar tothe processes described with reference to FIGS. 5 to 10 may be performedto form the first metal bump structure 240 including first to thirdmetal patterns 242, 244, and 246.

The first metal bump structure 240 may be substantially the same as orsimilar to the second metal bump structure 340. Thus, same or likereference numerals will be used to refer to the same or like elementsand repeated descriptions of the same elements may be omitted.

As illustrated in FIG. 15, the first wafer W1 may be cut along thescribe lane region SA to form an individualized first semiconductor chip200.

Referring to FIGS. 16 and 17, a plurality of the first semiconductorchips 200 may be arranged on the second wafer W2. The firstsemiconductor chip 200 may be bonded to the second semiconductor chip ofthe second wafer W2.

As illustrated in FIG. 16, after arranging the second wafer W2 to besupported on a carrier substrate, the first semiconductor chips 200 maybe arranged on the second wafer W2 corresponding to the die regions DA.The first semiconductor chip 200 may be stacked on the second wafer W2such that the first surface 212 of the first semiconductor chip 200faces the second wafer W2.

The first semiconductor chips 200 may be attached on the secondsemiconductor chips of the second wafer W2 by performing a thermalcompression process at a predetermined temperature (e.g., a temperaturerange of about 380° C. to about 450° C.). By the thermal compressionprocess, the first metal bump structure 240 of the first semiconductorchip 200 and the second metal bump structure 340 may be directly bondedto each other (e.g., Cu—Cu Bonding).

As illustrated in FIG. 17, a junction surface I may be formed betweenthe third metal pattern 246 of the first metal bump structure 240 andthe third metal pattern 346 of the second metal bump structure 340.

Since the second metal patterns 244 and 344 respectively disposed on thethird metal patterns 246 and 346 include a metal haying the coefficientof thermal expansion greater than that of copper, a local load may beapplied to the third metal patterns 246 and 346 to induce a sufficientdiffusion at the junction I between the first metal bump structure 240and the second metal bump structure 340 during the high-temperaturethermal compression process, thereby providing excellent bondingproperties.

Referring to FIG. 18, a filling support layer 400 may be formed to filla space between adjacent first semiconductor chips 200 and between thefirst semiconductor chip 200 and the second wafer W2.

In an exemplary embodiment of the present inventive concept, the fillingsupport layer 400 may be formed on the second wafer W2 to fill the spacebetween adjacent first semiconductor chips 200 and between the firstsemiconductor chip 200 and the second wafer W2. The filling supportlayer 400 may be formed to at least partially surround the firstsemiconductor chip 200. For example, an upper surface of the fillingsupport layer 400 may be substantially coplanar with an upper surface ofthe first semiconductor chip 200. For example, the filling support layer400 may be formed by a molding process, a dispensing process, or a spincoating process. For example, the filling support layer 400 may includea thermosetting resin or the like.

Referring to FIGS. 19 and 20, a second surface 214 of the firstsemiconductor chip 200 may be grinded to expose the through electrode250 and a second pad 260 may be formed on the second surface 214 of thefirst semiconductor chip 200.

An insulating layer 262 may be formed on the second surface 214 of thefirst semiconductor chip 200. The insulating layer 262 may includeopenings exposing the second pad 260. The second pad 260 may be formedon a first end portion of the through electrode 250.

When the through electrode 250 is formed by a via last process, the stepof forming the second pad 260 may be performed at or after forming thethrough electrode 250.

Referring to FIG. 21, the carrier substrate C may be removed from thesecond wafer W2, and then, the second wafer W may be cut along thescribe lane region SA to form an individualized second semiconductorchip. A filling support layer pattern 402, which may be an adhesivemember, may be interposed between the first and second semiconductorchips 200 and 300.

Then, the stacked first and second semiconductor chips 200 and 300 maybe mounted on a package substrate. In addition, a molding member may beformed on an upper surface of the package substrate to cover the firstand second semiconductor chips 200 and 300, and then, outer connectionmembers may be formed on outer connection pads on a lower surface of thepackage substrate to form the semiconductor package in FIG. 1.

in this embodiment, the first and second metal bump structures 240 and340 are bonded to each other by a die-to-wafer bonding method, however,the present inventive concept may not be limited thereto. For example,it may be understood that the first and second metal bump structures 240and 340 may be bonded to each other by a die-to-die bonding method or awafer-to-wafer bonding method.

FIG. 22 is a cross-sectional view illustrating a semiconductor packagein accordance with an exemplary embodiment of the present inventiveconcept. The semiconductor package may be substantially the same as orsimilar to the semiconductor package described with reference to FIGS. 1and 2 except for configurations of metal bump structures. Thus, samereference numerals will be used to refer to the same or like elementsand any further repetitive explanation concerning the above elements maybe omitted.

Referring to FIG. 22, a conductive connector of a semiconductor packagemay include a first metal bump structure 240 and a second metal bumpstructure 340. The first metal bump structure 240 may be provided on afirst pad 230 of a first semiconductor chip 200, and the second metalbump structure 340 may be provided on a third pad 330 of a secondsemiconductor chip 300.

In an exemplary embodiment of the present inventive concept, the firstmetal bump structure 240 may include first to third metal patterns 242,244, and 246 sequentially stacked on the first pad 230. The first andthird metal patterns 242 and 246 may serve as a main pattern. The firstmetal pattern 242 may serve as a first main pattern, and the secondmetal pattern 246 may serve as a second main pattern. The second metalpattern 244 may serve as a sub pattern and may be provided within themain pattern.

The first metal pattern 242 may have a first width W1. The second metalpattern 244 may have a second width W2, and the third metal pattern 246may have a third width W3. The third width W3 of the third metal pattern346 may be the same as the first width W1 of the first metal pattern342. However, the present inventive concept is not limited thereto. Forexample, the third metal pattern 346 may have a width different fromthat of the first metal pattern 342.

In an exemplary embodiment of the present inventive concept, each of thefirst metal pattern 242 and the third metal pattern 246 may have acuboid shape, a cylindrical shape or a triangular prism shape. However,the present inventive concept is not limited thereto.

The second metal pattern 244 may cover a central region of the firstmetal pattern 242, and the third metal pattern 246 may be provided onthe first metal pattern 242 to cover the second metal pattern 244. Forexample, the second metal pattern 244 may have a cylindrical shape.Accordingly, side surfaces and an upper surface of the second metalpattern 244 may be covered by the third metal pattern 246.

Similarly, the second metal bump structure 340 may include first tothird metal patterns 342, 344, and 346 sequentially stacked on the thirdpad 330.

Upper surfaces of the third metal patterns 246 and 346, for example,bonding surfaces may have a dishing type according to a plating solutionor an additive in an electroplating process. When the upper surfaces ofthe third metal patterns 246 and 346 come into contact with each otherand since the second metal patterns 244 and 344 are located in thecentral regions of the respective third metal patterns 246 and 346, alocal load may be applied to the central portions of the third metalpatterns 246 and 346 during a high-temperature thermo compressionbonding process to provide excellent bonding properties.

Hereinafter, a method of manufacturing the semiconductor package in FIG.22 will be explained.

FIGS. 23 to 29 are cross-sectional views illustrating a method ofmanufacturing a semiconductor package in accordance with an exemplaryembodiment of the present inventive concept.

Referring to FIGS. 23 to 29, a second metal bump structure 340 may beformed on a third pad 330 of a second semiconductor chip.

As illustrated in FIG. 23, processes the same as or similar to theprocesses described with reference to FIGS. 3 to 7 may be performed toform a first metal pattern 342 on the third pad 330.

In an exemplary embodiment of the present inventive concept, a firstplating process may be performed on a seed layer 22 to form the firstmetal pattern 342 including a first metal material.

For example, the first metal material may include copper (Cu). The firstmetal pattern 342 may have a first coefficient of thermal expansion. Thefirst metal pattern 342 may have a first thickness T1. The firstthickness T1 of the first metal pattern 342 may be within a range ofabout 1 μm to about 20 μm. The first metal pattern 342 may have a firstwidth W1. The first width W1 of the first metal pattern 342 may bewithin a range of about 2 μm to about 15 μm.

A first photoresist pattern used in the first plating process may beremoved from a substrate 310 to form the first metal pattern 342 on thethird pad 330 of the substrate 310. The seed layer 22 may be partiallyetched to form a seed layer pattern 24.

As illustrated in FIG. 24, a second photoresist pattern 32 may be formedon a first surface 312 of the substrate 310 to cover a portion of thefirst metal pattern 342.

A photoresist layer may be formed on the first surface 312 of thesubstrate 310 to cover the first metal pattern 342, and an exposureprocess may be performed on the photoresist layer to form the secondphotoresist pattern 32 having a second opening 33 that exposes a centralregion of the first metal pattern 342.

As illustrated in FIGS. 25 and 26, a second plating process may beperformed on the first metal pattern 342 exposed by the secondphotoresist pattern 32 to form a second metal pattern 344 including asecond metal material, and the second photoresist pattern 32 may beremoved from the substrate 310.

The second metal pattern 344 may have a cylindrical shape having asecond thickness T2. The second metal pattern 344 may cover the centralregion of the first metal pattern 342 and expose a peripheral region ofthe first metal pattern 342. For example, the second metal pattern 344may expose edges of the first metal pattern 342.

For example, the second metal material may include zinc (Zn), aluminum(Al), silver (Ag), etc. The second metal material may have a secondcoefficient of thermal expansion greater than the first coefficient ofthermal expansion of the first metal material. The second metal pattern344 may have a second thickness T2 smaller than the first thickness T1.A second width W2 of the second metal pattern 344 may be smaller thanthe first width W1 of the first metal pattern 342.

As illustrated in FIG. 27, a third photoresist pattern 34 may be formedon the first surface 312 of the substrate 310 and may expose the firstand second metal patterns 342 and 344.

A photoresist layer may be formed on the first surface 312 of thesubstrate 310 to cover the first and second metal pattern 342 and 344,and an exposure process may be performed on the photoresist layer toform the third photoresist pattern 34 having a third opening 35 thatexposes upper surfaces of the first and second metal patterns 342 and344.

As illustrated in FIG. 28, a third plating process may be performed onthe first and second metal patterns 342 and 344 exposed by the thirdphotoresist pattern 34 to form a third metal pattern 346 including athird metal material.

The third metal pattern 346 may be formed on the first metal pattern 342to cover the second metal pattern 344. Side surfaces and the uppersurface of the second metal pattern 344 may be covered by the thirdmetal pattern 346.

For example, the third metal material may include the same metal as thefirst metal material. The third metal pattern 346 may have a thirdthickness T3 smaller than the second thickness T2 of the second metalpattern 344. A third width W3 of the third metal pattern 346 may begreater than the second width W2 of the second metal pattern 344 and maybe the same as the first width W1 of the first metal pattern 342.

As illustrated in FIG. 29, the third photoresist pattern 34 may beremoved from the substrate 310 to form the second metal bump structure340 including the first to third metal patterns 342, 344, and 346 on thethird pad 330 of the substrate 310.

Then, processes the same as or similar to the processes described withreference to FIGS. 12 to 15 and 23 to 29 may be performed to form afirst metal bump structure 240 on a first pad 230 of the firstsemiconductor chip.

Then, processes the same as or similar to the processes described withreference to FIGS. 16 to 21 may be performed to bond the first andsecond semiconductor chips to each other to provide the semiconductorpackage in FIG. 21.

FIG. 30 is a cross-sectional view illustrating a semiconductor packagein accordance with an exemplary embodiment of the present inventiveconcept. The semiconductor package may be substantially the same as orsimilar to the semiconductor package described with reference to FIGS. 1and 2 except for configurations of metal bump structures. Thus, samereference numerals will be used to refer to the same or like elementsand any further repetitive description concerning the above elements maybe omitted.

Referring to FIG. 30, a first metal bump structure 240 may include firstto third metal patterns 242, 244, and 246 sequentially stacked on afirst pad 230. The first and third metal patterns 242 and 246 may be amain pattern. The first metal pattern 242 may be a first main pattern,and the second metal pattern 246 may be a second main pattern. Thesecond metal pattern 244 may be a sub pattern and may be provided withinthe main pattern.

The second metal pattern 244 may have, for example, an annular shapecovering a peripheral region of the first metal pattern 242, and thethird metal pattern 246 may be provided on the first metal pattern 242to cover the second metal pattern 244. Accordingly, side surfaces of thesecond metal pattern 244 may be exposed to the outside, in an exemplaryembodiment of the present inventive concept, the second metal pattern244 may have a polygonal shape with an opening.

Similarly, the second metal bump structure 340 may include first tothird metal patterns 342, 344, and 346 sequentially stacked on the thirdpad 330.

Upper surfaces of the third metal patterns 246 and 346 may be bondingsurfaces and may have a doming type according to a plating solution oran additive in an electroplating process. For example, the upper surfaceof the third metal pattern 346 of the second metal bump structure 340may be a lower surface when disposed on the upper surface of the thirdmetal pattern 246 of the first metal bump structure 240. When the uppersurfaces of the third metal patterns 246 and 346 come into contact witheach other and since the second metal patterns 244 and 344 arerespectively located in peripheral regions of the third metal patterns246 and 346, a local load may be applied to the peripheral portions ofthe third metal patterns 246 and 346 during a high-temperature thermocompression bonding process to provide excellent bonding properties.

Hereinafter, a method of manufacturing the semiconductor package in FIG.30 will be explained.

FIGS. 31 to 36 are cross-sectional views illustrating a method ofmanufacturing a semiconductor package in accordance with an exemplaryembodiment of the present inventive concept.

Referring to FIGS. 31 to 36, a second metal bump structure 340 may beformed on a third pad 330 of a second semiconductor chip 300.

As illustrated in FIG. 31, the processes to form the first metal pattern342 described with reference to FIGS. 3 to 7 may be performed to form afirst metal pattern 342 on the third pad 330, and a second photoresistpattern 32 may be formed on a first surface 312 of a substrate 310 toform a second photoresist pattern 32.

A photoresist layer may be formed on the first surface 312 of thesubstrate 310 to cover the first metal pattern 342, and an exposureprocess may be performed on the photoresist layer to form the secondphotoresist pattern 32 having a second opening 33 that exposes aperipheral region of the first metal pattern 342.

As illustrated in FIGS. 32 and 33, a second plating process may beperformed on the first metal pattern 342 exposed by the secondphotoresist pattern 32 to form a second metal pattern 344 including asecond metal material, and the second photoresist pattern 32 may beremoved from the substrate 310.

The second metal pattern 344 may have, for example, an annular shapehaving a second thickness T2. However, the present inventive concept isnot limited thereto. For example, the second metal pattern 344 may havea polygonal shape with an opening. The second metal pattern 344 maycover a peripheral region of the first metal pattern 342 and expose acentral region of the first metal pattern 342.

As illustrated in FIG. 34, a third photoresist pattern 34 may be formedon the first surface 312 of the substrate 310 to expose the first andsecond metal patterns 342 and 344.

A photoresist layer may be formed on the first surface 312 of thesubstrate 310 to cover the first and second metal pattern 342 and 344,and an exposure process may be performed on the photoresist layer toform the third photoresist pattern 34 having a third opening 35 thatexposes upper surfaces of the first and second metal patterns 342 and344.

As illustrated in FIG. 35, a third plating process may be performed onthe first and second metal patterns 342 and 344 exposed by the thirdphotoresist pattern 34 to form a third metal pattern 346 including athird metal material.

The third metal pattern 346 may be formed on the first metal pattern 342to cover the second metal pattern 344. Side surfaces of the second metalpattern 344 may be exposed from the third metal pattern 346. Forexample, inner surfaces of the second metal pattern 344 may be coveredby the third metal pattern 346.

As illustrated in FIG. 36, the third photoresist pattern 34 may beremoved from the substrate 310 to form the second metal bump structure340 including the first to third metal patterns 342, 344, and 346 on thethird pad 330 of the substrate 310.

Then, processes that are the same as or similar to the processesdescribed with reference to FIGS. 12 to 15 and 31 to 36 may be performedto form a first metal bump structure 240 on a first pad 230 of the firstsemiconductor chip 200.

Then, processes that are the same as or similar to the processesdescribed with reference to FIGS. 16 to 21 may be performed to bond thefirst and second semiconductor chips 200 and 300 to each other to formthe semiconductor package in FIG. 30.

FIG. 37 is a cross-sectional view illustrating a semiconductor packagein accordance with an exemplary embodiment of the present inventiveconcept. The semiconductor package may be substantially, the same as orsimilar to the semiconductor package described with reference to FIGS. 1and 2 except that the semiconductor package has a 2.5D packageconfiguration. Thus, the same reference numerals will be used to referto the same or like elements and any further repetitive descriptionconcerning the above elements may be omitted.

Referring to FIG. 37, a semiconductor package 11 may include a packagesubstrate 100, an interposer 600, a first semiconductor device 200 and asecond semiconductor device 700.

In an exemplary embodiment of the present inventive concept, thesemiconductor package 11 may include a memory device having a stackedchip structure in which a plurality of dies (chips) is stacked. Forexample, the semiconductor package 11 may include a semiconductor devicewith a 25D chip structure. In this case, the first semiconductor device200 may include, for example, a logic semiconductor device, and thesecond semiconductor device 700 may include, for example, a memorydevice. The logic semiconductor device may include, for example, acentral processing unit (CPU), a graphic processing unit (GPU), anapplication-specific integrated circuit (ASIC), or a system on chip(SOC). For example, the memory device may include a high bandwidthmemory device.

In an exemplary embodiment of the present inventive concept, the packagesubstrate 100 may have opposite lower and upper surfaces. For example,the package substrate 100 may be a printed circuit board (PCB). The PCBmay be a multilayered circuit board including vias and various circuitstherein.

The interposer 600 may be disposed on the package substrate 100. Theinterposer 600 may be mounted on the package substrate 100 by solderbumps 662. For example, a planar area of the interposer 600 may be lessthan a planar area of the package substrate 100. The interposer 600 maybe disposed within the area of the package substrate 100 in a plan view.

The interposer 600 may be, for example, a silicon interposer including aplurality of connecting wiring lines therein. The first semiconductordevice 200 and the second semiconductor device 700 may be connected toeach other through the connecting wiring lines and/or may beelectrically connected to the package substrate 100 through the solderbumps 662. The silicon interposer may provide a high densityinterconnection between the first and second semiconductor devices 200and 700.

For example, the interposer 600 may include a semiconductor substrate610 and/or a wiring layer 620 including a plurality of wiring lines onthe semiconductor substrate 610. For example, the plurality of wiringlines may be disposed on an upper surface of the semiconductor substrate610. A plurality of the wiring lines may include first wiring lines 622and/or second wiring lines 624. The semiconductor substrate 610 mayinclude a plurality of through electrodes 660 passing therethrough. Eachof the through electrodes 660 may include a through-silicon via (TSV).

In an exemplary embodiment of the present inventive concept, the firstand second semiconductor devices 200 and 700 may be disposed on theinterposer 600. The first and second semiconductor devices 200 and 700may be mounted on the interposer 600 such that chip pads of the firstand second semiconductor devices 200 and 700 face the interposer 600.The chip pads of the first and second semiconductor devices 200 and 700may be electrically connected to pads of the interposer 600 by theconductive connector in FIG. 1.

For example, a second metal bump structure 240 of the firstsemiconductor device 200 and a first metal bump structure 640 of theinterposer 600 may be bonded to each other to sever as an electricalconnector for electrically connecting the first semiconductor device 200and the interposer 600 to each other. For example, the first metal bumpstructure 640 and the second metal bump structure 240 may be at leastpartially surrounded by a first mold layer 350 (or, e.g., a fill layer).

A second metal bump structure 740 of the second semiconductor device 700and a first metal bump structure 640 of the interposer 600 may be bondedto each other to sever as an electrical connector for electricallyconnecting the second semiconductor device 700 and the interposer 600 toeach other. For example, the first metal bump structure 640 and thesecond metal bump structure 740 may be at least partially surrounded bya second mold layer 450 (or, e.g., a fill layer).

The interposer 600 may be mounted on the package substrate 100 throughsolder bumps 662. For example, the solder bump 662 may include C4 bump.A pad 680 of the interposer 600 may be electrically connected to asubstrate pad of the package substrate 100 by the solder bump 662.

As mentioned above, the first and second semiconductor devices 200 and700 of the semiconductor package 11 having a 2.5D chip structure may beelectrically connected to the interposer 600 by the conductive connectorin FIG. 1.

In addition, the semiconductor package 11 may be a semiconductor memorydevice having a 3D chip structure. In this case, the semiconductorpackage 11 may include a first semiconductor device 200 and a secondsemiconductor device 700 sequentially stacked on a package substrate100. The first semiconductor device 200 and the second semiconductordevice 700 may be electrically connected to each other by the conductiveconnector in FIG. 1.

In an exemplary embodiment of the present inventive concept, thesemiconductor package 11 may be a fan-out stack package includingsequentially stacked first and second semiconductor devices 200 and 700.In this case, the first semiconductor device 200 and the secondsemiconductor device 700 may be electrically connected to each other bythe conductive connector in FIG. 1.

The semiconductor package 11 may include semiconductor devices such aslogic devices or memory devices. The semiconductor package 11 mayinclude logic devices such as central processing units (CPUs), mainprocessing units (MPUs), or application processors (APs), or the like,and volatile memory devices such as dynamic random access memory (DRAM)devices, high bandwidth memory (HBM) devices, or non-volatile memorydevices such as flash memory devices, parameter random access memory(PRAM) devices, magneto-resistive random-access memory (MRAM) devices,resistive random-access memory (ReRAM) devices, or the like.

While the present inventive concept has been described with reference toexemplary embodiments thereof, it will be understood by those ofordinary skill in the art that various changes in form and details maybe made thereto without departing from the spirit and scope of thepresent inventive concept.

What is claimed is:
 1. A semiconductor package, comprising: a firstsemiconductor device including a first pad and a first metal bumpstructure provided on the first pad; and a second semiconductor devicestacked on the first semiconductor device and including a third pad anda second metal bump structure provided on the third pad, wherein thefirst and second metal bump structures are bonded to each other to forma conductive connector that electrically connects the first and secondsemiconductor devices to each other, wherein each of the first andsecond metal bumps structures includes first, second and third metalpatterns, wherein the first, second and third metal patterns of thefirst metal bump structure are stacked on the first pad, wherein thefirst, second and third metal patterns of the second metal bumpstructure are stacked on the third pad, and wherein the first and thirdmetal patterns include a first metal having a first coefficient ofthermal expansion, and the second metal pattern includes a second metalhaving a second coefficient of thermal expansion greater than the firstcoefficient of thermal expansion.
 2. The semiconductor package of claim1, wherein the first metal includes copper (Cu).
 3. The semiconductorpackage of claim 2, wherein the second metal includes at least one ofzinc (Zn), aluminum (Al) or silver (Ag).
 4. The semiconductor package ofclaim 1, wherein diameters of the first and second metal bumpstructures, respectively, are within a range of about 2 μm to about 15μm.
 5. The semiconductor package of claim 1, wherein the first metalpattern has a first thickness, wherein the second metal pattern has asecond thickness smaller than the first thickness, and wherein the thirdmetal pattern has a third thickness smaller than or the same as thesecond thickness.
 6. The semiconductor package of claim 5, wherein thefirst thickness is within a range of about 70% to about 85% of the wholethickness of each of the first and second metal bump structures, whereinthe second thickness is within a range of about 10% to about 20% of thewhole thickness of each of the first and second metal bump structures,and the third thickness is within a range of about 5% to about 10% ofthe whole thickness of each of the first and second metal bumpstructures.
 7. The semiconductor package of claim 1, wherein the firstmetal pattern has a first width, wherein the second metal pattern has asecond width smaller than the first width, and wherein the third metalpattern has a third width greater than the second width.
 8. Thesemiconductor package of claim 7, wherein the second metal pattern has acylindrical shape covering a central region of the first metal pattern,and the third metal pattern is provided on the first metal pattern tocover the second metal pattern.
 9. The semiconductor package of claim 7,wherein the second metal pattern has an annular shape covering aperipheral region of the first metal pattern, and the third metalpattern is provided on the first metal pattern to cover the second metalpattern.
 10. The semiconductor package of claim 9, wherein an outersurface of the second metal pattern is exposed from the third metalpattern.
 11. A semiconductor package, comprising: a first semiconductordevice including a first pad and a first metal bump structure providedon the first pad; and a second semiconductor device stacked on the firstsemiconductor device, and including a third pad and a second metal bumpstructure provided on the third pad, wherein each of the first andsecond metal bump structures includes: a main pattern including copper(Cu), wherein the main pattern of the first metal bump structure isprovided on the first pad, and the main pattern of the second metal bumpstructure is provided on the third pad; and a sub pattern providedinside the main pattern adjacent to a junction surface and including asecond metal having a coefficient of thermal expansion greater than thatof copper (Cu), and wherein the junction surface is formed by thebonding between a first surface of the main pattern of the first metalbump structure and a first surface of the main pattern of the secondmetal bump structure.
 12. The semiconductor package of claim 11, whereinthe second metal includes at least one of zinc (Zn), aluminum (Al) orsilver (Ag).
 13. The semiconductor package of claim 11, whereindiameters of the first and second metal bump structures, respectively,are within a range of about 2 μm to about 15 μm.
 14. The semiconductorpackage of claim 11, wherein the main pattern of each of the first andsecond metal bump structures has a cuboid shape or a cylindrical shape,and the sub pattern of each of the first and second metal bumpstructures has a cylindrical shape having a first thickness.
 15. Thesemiconductor package of claim 14, wherein an outer surface of the subpattern of each of the first and second metal bump structures isrespectively covered by the main pattern of each of the first and secondmetal bump structures.
 16. The semiconductor package of claim 11,wherein the main pattern of each of the first and second metal bumpstructures has a cuboid shape or a cylindrical shape, and the subpattern of each of the first and second metal bump structures has anannular shape having a first thickness, and wherein an outer surface ofthe sub pattern of each of the first and second metal bump structures isrespectively exposed by the main pattern of each of the first and secondmetal bump structures.
 17. A semiconductor package, comprising: apackage substrate; a first semiconductor chip stacked on the packagesubstrate, and including a first pad and a first metal bump structureprovided on the first pad; and a second semiconductor chip stacked onthe first semiconductor chip, and including a third pad and a secondmetal bump structure provided on the third pad, wherein the first andsecond metal bump structures are bonded to each other to form aconductive connector that electrically connects the first and secondsemiconductor chips to each other, wherein each of the first and secondmetal bumps structures includes first, second and third metal patterns,wherein the first, second and third metal patterns of the first metalbump structure are stacked on the first pad, wherein the first, secondand third metal patterns of the second metal bump structure are stackedon the third pad, wherein the first and third metal patterns includescopper (Cu), and the second metal pattern includes a metal having acoefficient of thermal expansion greater than that of copper (Cu), andwherein diameters of the first and second metal bump structures,respectively, are within a range of about 2 μm to about 15 μm.
 18. Thesemiconductor package of claim 17, wherein the metal includes at leastone of zinc (Zn), aluminum (Al) or silver (Ag).
 19. The semiconductorpackage of claim 17, wherein the first metal pattern has a firstthickness, wherein the second metal pattern has a second thicknesssmaller than the first thickness, and wherein the third metal patternhas a third thickness smaller than or the same as the second thickness.20. The semiconductor package of claim 19, wherein the first thicknessis within a range of about 70% to about 85% of the whole thickness ofeach of the first and second metal bump structures, wherein the secondthickness is within a range of about 10% to about 20% of the wholethickness of each of the first and second metal bump structures, and thethird thickness is within a range of about 5% to about 10% of the wholethickness of each of the first and second metal bump structures.